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x86/hyperv: Add a function to read both TSC and TSC page value simulateneously 

This is going to be used from KVM code where both TSC and TSC page value
are needed.

Nothing is supposed to use the function when Hyper-V code is compiled out,
just BUG().

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: kvm@vger.kernel.org
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: "Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>
Cc: Roman Kagan <rkagan@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: devel@linuxdriverproject.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Cathy Avery <cavery@redhat.com>
Cc: Mohammed Gamal <mmorsy@redhat.com>
Link: https://lkml.kernel.org/r/20180124132337.30138-3-vkuznets@redhat.com
hifive-unleashed-5.1
Vitaly Kuznetsov 2018-01-24 14:23:32 +01:00 committed by Thomas Gleixner
parent 89a8f6d490
commit e2768eaa1c
2 changed files with 20 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/x86/hyperv/hv_init.c
View File

@ -37,6 +37,7 @@ struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
{
return tsc_pg;
}
EXPORT_SYMBOL_GPL(hv_get_tsc_page);
static u64 read_hv_clock_tsc(struct clocksource *arg)
{

23
arch/x86/include/asm/mshyperv.h
View File

@ -325,9 +325,10 @@ static inline void hyperv_setup_mmu_ops(void) {}
#ifdef CONFIG_HYPERV_TSCPAGE
struct ms_hyperv_tsc_page *hv_get_tsc_page(void);
static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg)
static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg,
u64 *cur_tsc)
{
u64 scale, offset, cur_tsc;
u64 scale, offset;
u32 sequence;
/*
@ -358,7 +359,7 @@ static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg)
scale = READ_ONCE(tsc_pg->tsc_scale);
offset = READ_ONCE(tsc_pg->tsc_offset);
cur_tsc = rdtsc_ordered();
*cur_tsc = rdtsc_ordered();
/*
* Make sure we read sequence after we read all other values
@ -368,7 +369,14 @@ static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg)
} while (READ_ONCE(tsc_pg->tsc_sequence) != sequence);
return mul_u64_u64_shr(cur_tsc, scale, 64) + offset;
return mul_u64_u64_shr(*cur_tsc, scale, 64) + offset;
}
static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg)
{
u64 cur_tsc;
return hv_read_tsc_page_tsc(tsc_pg, &cur_tsc);
}
#else
@ -376,5 +384,12 @@ static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
{
return NULL;
}
static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg,
u64 *cur_tsc)
{
BUG();
return U64_MAX;
}
#endif
#endif